European Journal of Wood and Wood Products最新文献

Fast-growing poplar wood is limited by poor dimensional stability and biological durability, while conventional treatment methods (such as involving toxic wood preservatives) often raise environmental and health concerns. Furthermore, some emerging chemical modification techniques, such as acetylation and furfurylation, are relatively expensive, which increases the final product cost. To address these challenges, we propose a bio-based sustainable approach: impregnating poplar wood with a hybrid system (GCA) composed of two lower-cost bio-based chemicals, citric acid (CA) and glycerol (G), to induce in-situ esterification without generating harmful by-products. The modification mechanism involves the formation of a robust, cross-linked GCA polyester network within the wood cell wall, leading to comprehensive performance enhancements. The dimensional stability was substantially improved, with a 64% anti-swelling efficiency. This is primarily attributed to the network restricting the wood’s interaction with moisture, particularly cell-wall-associated bound water, as confirmed by LFNMR analysis. The reinforcing network also significantly enhanced mechanical properties, including a 65% increase in modulus of elasticity and a 57% increase in compressive strength. Moreover, the GCA-modified wood demonstrated exceptional durability, exhibiting enhanced ultraviolet resistance with greater color stability, a remarkable reduction in mass loss against decay fungi, and complete inhibition of mold growth. This environmentally friendly and effective strategy presents a promising pathway for converting low-grade wood into a high-performance, durable material suitable for demanding construction and outdoor applications.

Wood modification through polyesterification enhances its dimensional stability and reduces its moisture uptake. The efficacy of this modification depends on the placement of the polymeric networks within the wood. When these networks are situated within the cell wall, they cause cell wall bulking, thereby reducing the potential volume for moisture, which improves dimensional stability and water repellence capacity. The anti-swelling efficiency is typically calculated by comparing the dimensions of untreated and treated samples in both saturated and anhydrous states. The definition of the saturated state can influence the anti-swelling efficiency value. While it is established that polyesterification reduces wood moisture uptake, the kinetics of moisture absorption before and after modification have not been extensively studied. In this study, we demonstrate that the modification of four North American wood species with a mixture of whey ultrafiltration permeate and citric acid significantly enhances their physical properties as previously studied, as evidenced by increased anti-swelling efficiency. We also show that while wood modification deeply alters the kinetics of moisture uptake, it effectively reduces overall moisture absorption.

Trees of the species Anadenanthera colubrina (Vell.) Brenan, Cenostigma pyramidale (Tul.) E. Gagnon & G.P. Lewis, Capparidastrum frondosum (Jacq.) Cornejo & Iltis, Commiphora leptophloeos (Mart) J.B. Gillett, Mimosa tenuiflora (Willd.) Poir., Manihot baccata Allem, Guapira sp. and Aspidosperma pyrifolium Mart. & Zucc (Pereiro) were collected in the municipality of Santa Cruz, Rio Grande do Norte State, Brazil. Discs were cut at 0% (10 cm above ground), 25%, 50%, 75% and 100% of commercial height, and at diameter at breast height. Reflectance spectra and data on luminosity (L*) and chromatic coordinates of green-red axis (a*) and blue-yellow axis (b*) were obtained and chroma (C*) and hue angle (h) were calculated. Mean values and standard deviations of color parameters by species indicated Capparidastrum frondosum, Commiphora leptophloeos, Manihot baccata, Guapira sp. and Aspidosperma pyrifolium as light species, and Anadenanthera colubrina, Cenostigma pyramidale and Mimosa tenuiflora as dark species. Colorimetric parameters and reflectance spectra of the wood of eight Caatinga species varied in axial trunk position, from tree base to top, but not in a linear pattern and there was no influence on species discrimination. Parameters L* and a* showed more potential for distinction of wood from evaluated Caatinga trees. Tree height, commercial and total, had correlation from − 0.51 to -0.64, with parameter b* and − 0.56 to -0.61 with C*, and DBH had low correlation (maximum of -0.26) with colorimetric parameters.

Copper-based preservatives remain crucial for protecting timber from fungal decay for wood in direct soil contact, yet the presence of copper tolerant brown-rot fungi poses a risk to long-term service life, especially where treatment penetration is shallow. Fomitopsis ostreiformis is an aggressive brown rot species found across Australian field trials but lacks established copper tolerance thresholds. This study used in vitro petri dish growth assays and soil jar decay tests to assess the copper tolerance of F. ostreiformis. Fungal growth on amended malt extract agar was not inhibited at 1000 ppm of copper. Soil block tests of copper sulphate treated Pinus radiata suggested a copper threshold of approximately 1760 ppm to inhibit this fungus. In the soil jar decay tests, leached samples had lower mass losses than non-leached samples, suggesting that the leaching process potentially improved copper redistribution. These findings highlight the copper tolerance of F. ostreiformis, with implications for the effectiveness of shallow treatments against this fungus. Further tests using copper with a co-biocide are recommended.

The aim of this study was to assess the potential of the fungus Phellinus linteus in the biopulping process of Pinus sp. and Eucalyptus sp. woods chips. The physical and chemical properties of wood chips, their behavior during the Kraft pulping process, as well as the quality of the cellulose pulp and paper produced, were evaluated. Basic density, extractive content, and lignin content were lower in the biotreated wood chips compared to the control. Eucalyptus and Pinus woods treated with Phellinus linteus required less active alkali for cooking, with 20.8% active alkali for Eucalyptus and 21.1% for Pinus, respectively. A higher gross yield was observed in the treated Eucalyptus sp. chips, while Pinus sp. chips showed no significant difference compared to the control. Paper strength was greater in the biotreated Eucalyptus, whereas in Pinus, the untreated chips exhibited higher strength. The fungus Phellinus linteus shows potential for use in the biopulping process, with reduced chemical consumption and benefits in yield and paper quality.

Understanding the hierarchical and three-dimensional (3D) anatomy of wood is crucial for applications and advanced studies in wood science. However, teaching and learning this intricate anatomy can be challenging at times when relying solely on traditional two-dimensional (2D) teaching materials. To address this challenge, this article introduces a comprehensive 3D in situ visualization of softwood and hardwood structures using X-ray micro-computed tomography. Two types of visualization, full-structure and lumen-based 3D renderings, were used to exemplify the spatial morphology and features of the main anatomical structures, including tracheids, parenchyma cells, vessels, fibers, and inorganic inclusions. To complement these illustrations, selected features were also measured in 3D to describe their shape and dimensions. This article is intended as a reference resource for students, providing insights into how wood structures appear in three dimensions, and for lecturers as a supplement resource to create engaging teaching materials. Supplementary images and 3D models of wood structures are included in this article, which can be used as an advanced and supplementary toolkit for interactive viewing or 3D printing in various educational settings. This approach aims to foster the greater accessibility, interest, and understanding of the 3D wood anatomy for both students and lecturers.

Banded laminated-veneer lumber (LVL-C) is an engineered wood product valued for its high bending, tensile and compressive strength along the grain, making it well-suited for long-span, high-load members such as composite LVL I-beams. In these beams, the web is usually a unidirectional LVL, whereas the flanges are fabricated from cross-banded LVL-C to improve dimensional stability and rolling-shear resistance. This study investigates the mechanical performance of nailed LVL–LVL-C connections that link the flange to the web. Sixty push-out shear tests were carried out on eight configurations, varying (i) nail type, (ii) nail spacing (45 mm vs. 75 mm), and (iii) flange thickness (19 mm vs. 37 mm). The experiments show that flange thickness is the governing parameter: specimens with the thinner flange reached, on average, 18–20 % higher load capacity, whereas the thicker-flange specimens exhibited greater initial and secant stiffness. Two characteristic failure mechanisms were observed: single-hinge web yielding, in which one plastic hinge develops in the weak (web) member, and double-hinge composite yielding, in which a second plastic hinge forms in the strong (flange) member. These mechanisms correspond to Johansen modes (e) and (f). A nonlinear beam-on-foundation (BOF) model was developed for the nails; the model reproduces both observed failure mechanisms and the full load–slip response. Calibrating the model yields embedment strengths roughly three times the values predicted by prEN 1995-1-1, reducing the mean error in capacity prediction from 46 % to less than 1 %. A complementary linear BOF formulation confirms that the slip modulus is highly sensitive to the effective embedment depth, explaining the marked stiffness difference between the two flange thicknesses. In summary, the combined experimental–numerical programme (i) provides revised embedment parameters for spruce LVL and LVL-C, (ii) shows that current Eurocode provisions are overly conservative for these materials, and (iii) offers a validated BOF framework for designing nailed connections in LVL I-beams.

This study presents a comprehensive investigation of the bioactive properties of the condensate formed during the steaming treatment of beech wood (Fagus orientalis L.). The phenolic compound profile, antioxidant capacity, enzyme inhibition, and antimicrobial activity of the condensate were evaluated using multiple analytical methods. Rich in total phenolic content (339.20 mg GAE/g) and flavonoid levels (79.74 mg QE/g), the condensate exhibited strong reducing power in the ferric reducing antioxidant power assay (FRAP), while demonstrating moderate radical scavenging activity in the DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2′-azinobis (3-ethylbenzothiazoline 6-sulfonic acid)) tests. In antimicrobial assessments, the condensate was found to be effective against Gram-positive bacteria, Staphylococcus aureus and Bacillus cereus as well as Candida albicans as a pathogen fungus, while showing lower activity against Gram-negative bacteria. Its antifungal efficacy was found to be notable when compared to nystatin. Although the IC₅₀ value of the condensate in α-amylase inhibition assays (1320.00 µg/mL) was weaker than that of the reference inhibitor acarbose (33.26 µg/mL), the results indicate its potential as a plant-based enzyme inhibitor candidate. Fourier transform infrared (FTIR) spectroscopy revealed characteristic peaks associated with lignin derivatives, carbohydrates, and ester bonds in the condensate. LC–MS/MS analyses identified chlorogenic acid (1581.65 µg/g) as the major phenolic compound, along with ferulic acid and rosmarinic acid. Beech steaming condensate stands out as a valuable bioactive resource in the context of industrial by-product valorization. With its antioxidant, antimicrobial, and enzyme-inhibitory properties, it holds promising potential for applications in the food preservation, pharmaceutical, and cosmetic industries. These findings may contribute to the sustainability of the forest industry from a circular economy perspective.

This study presents a comprehensive analysis of the phytochemical profiles and biological activities of bark extracts from seven industrially significant tree species: Pinus sylvestris, Pinus nigra, Pinus brutia, Picea orientalis, Abies nordmanniana subsp. equi-trojani, Fagus orientalis, and Quercus robur. Bioactive compounds, including phenolics, flavonoids, and alkyl esters, were identified and quantified using GC-MS and HPLC techniques. A methanol: water mixture (65:35, v/v) was found to be the most effective solvent, yielding the highest total phenolic content in Abies nordmanniana and the highest flavonoid concentration in Pinus brutia. GC-MS analysis revealed species-specific distributions of key compounds such as 2-ethylhexanol, methyl stearate, and mono(2-ethylhexyl) adipate, reflecting the chemical diversity among the species. The extracts were further evaluated for their antioxidant, antimicrobial, and enzyme-inhibitory activities. Notably, inhibition of PPO and PON1 enzymes was observed, and DNA protection assays confirmed the ability of extracts to mitigate oxidative damage. These findings highlight the potential of industrial tree bark, typically a waste product of the wood industry, as a valuable source of bioactive compounds. The study advocates for its integration into the circular economy by developing high-value products for pharmaceutical, industrial, and environmental use.

A laminated bamboo sandwich panel with a grid core was developed, utilizing bamboo veneers for both surface and core layers. Four-point bending tests evaluated the effects of structural parameters—processing methods, grid count, and layer thickness—on ultimate load-carrying, deflection, strain, specific stiffness, and specific strength. The empirical results indicated that grid core processing significantly influences performance, with partition sandwich panels exhibiting 108.9% higher specific strength than interlocked sandwich panels. Increasing long grid numbers enhanced ultimate load-carrying capacity by 68.4% and specific strength by 41.7%, while short grids had minimal impact. Reducing lower layer thickness from 8 mm to 4 mm decreased specific strength by 24.2%, and reducing core thickness from 48 mm to 32 mm led to a 31.2% decline. Nonlinear load-deflection and load-strain behaviors were observed, and a simulation model successfully predicted structural performance. Compared to traditional materials, the laminated bamboo sandwich panel offers superior structural performance, reduced environmental impact, and cost reduction, making it highly suitable for construction applications such as flooring, wallboards, and bridge decks.